This invention relates to high speed motion picture photography and high illumination sources for use therein and in particular to a flashbulb control system for providing controlled light intensity over a given period of time.
Controlled high illumination over fixed periods of time is frequently required in high speed motion picture photography. As an example, a light source of 10.sup.7 tp 10.sup.8 lm for a period of 100 ms was required for high speed motion picture photography in the USAF "Have Host" test program. Although tungsten lamps were not capable of producing this it was found that low cost AG-1 flashbulbs would provide 4.times.10.sup.5 lm and last about 12 ms. It was determined that if 16 AG-1 bulbs were fired every 12 ms for 8 iterations, the correct intensity would be obtained over the time span required. The basic problem faced, however, was that of arranging and appropriately firing the bulbs in a sequence and time frame that would provide the required high illumination.
Since AG-1 bulbs five sympathetically if in contact with a fired bulb with a delay of about 12 ms it was proposed that 144 bulbs in 8 strings of 18 be cast in clear resin and the center two bulbs of each string ignited. The entire flash block did not ignite as planned however.
Other schemes for firing the bulbs in a controlled manner were also found to be ineffective. Furthermore most states-of-the-art systems were also found to be subject to premature and uncontrolled firing of bulbs as a result of spurious signals.
Accordingly, there currently exists the need for a high illumination flashbulb array with firing sequence control that utilizes inexpensive AG-1 flashbulbs and that is not subject to uncontrolled and premature firing from spurious signals. The present invention is directed toward satisfying that need.